The Syrian Army has reportedly taken control of a medieval castle on the hill overlooking the city of Palmyra as the government troops edge closer to reclaiming the historic site from Islamic State terrorists.

“The army units in cooperation with popular defense groups have taken control of the Tadmor [Palmyra] citadel after delivering significant losses to the terrorists,” SANA news agency reported, citing a military source.

The Syrian military began the storming of the Fakhr-al-Din al-Maani Castle, or Palmyra Castle, which was the last strategic height in the city held by the jihadists, on Friday morning.

“However, several units of the Syrian Army have managed to go in and break the defense line of the terrorists,” he added, citing sources on the ground.

There are casualties on both sides as a result of the fighting, the stringer said.

The operation to demine the area around the citadel is also currently underway.

“The Syrian Army said that military action aimed at taking control of the castle and the whole city is underway on all directions,” Isa said.

According to the stringer, Islamic State (IS, formerly ISIS/ISIL) terrorists are “feeling fear because of the success and suddenness of the Syrian Army’s operation” in Palmyra.

The jihadists also use car bombs and suicide bombers to stage attacks in the areas which have been taken under control by Syrian troops, he added.

Russian Foreign Minister Sergey Lavrov said on Friday that Moscow expects a Syrian Army operation to retake the ancient city of Palmyra from Islamic State, with the support of the Russian Air Force, to be successfully concluded soon.

"We’re counting on the operation to liberate Palmyra, which is now carried out by the Syrian Army with support from Russia’s Air Force, to be successfully completed in the nearest future," Lavrov stated.

Earlier in the day an army unit, in cooperation with the popular defense groups, dislodged Islamic State from the Syriatel hill near Palmyra Castle, a military source told Syrian state news agency SANA on Friday.

The government troops combed the hill after destroying the last IS hideouts and dismantled the explosive devices the militants left behind, the source said.

Several IS fighters were killed as the hill was taken, while the rest fled towards the city of Palmyra, leaving their weapons behind, he added.

A video posted by MilitaryMediaSy news outlet shows the army shelling militant positions with Palmyra Castle seen in the background.

The 13th-century Palmyra Castle, also known as Fakhr-al-Din al-Maani Castle, became a UNESCO World Heritage Site in 1980.

The Syrian Army and its allies have “regained control of the entrance to the city Palmyra” after the liberation of Palmyra Castle on Friday and height of Alseriaatal – on Thursday, another source told Sputnik.

On March 14, Russia announced that it is withdrawing the majority of its forces from Syria, as the five-month operation nears its goals.

However, Deputy Defense Minister Nikolay Pankov stressed that “it’s early to talk about victory over terrorism. The Russian aviation group is still tasked with striking terrorist targets.”

Palmyra is a UNESCO World Heritage Site, formerly known for housing some of the best-preserved monuments of antiquity anywhere in the world.

Since capturing it, the jihadists have blown up the 2,000-year-old Temple of Bel, and the Arch of Triumph, and have used the Roman-era amphitheater for filmed public executions.